drm/i915: provide FBC status in debugfs

Tools like powertop want to check the current FBC status and report it
to the user.  So add a debugfs file indicating whether FBC is enabled,
and if not, why.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 3afe361ec552..47805a41395e 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1249,6 +1249,7 @@ static void i915_setup_compression(struct drm_device *dev, int size)
         /* Leave 1M for line length buffer & misc. */
         compressed_fb = drm_mm_search_free(&dev_priv->vram, size, 4096, 0);
         if (!compressed_fb) {
+                dev_priv->no_fbc_reason = FBC_STOLEN_TOO_SMALL;
                 i915_warn_stolen(dev);
                 return;
         }
@@ -1256,6 +1257,7 @@ static void i915_setup_compression(struct drm_device *dev, int size)
         compressed_fb = drm_mm_get_block(compressed_fb, size, 4096);
         if (!compressed_fb) {
                 i915_warn_stolen(dev);
+                dev_priv->no_fbc_reason = FBC_STOLEN_TOO_SMALL;
                 return;
         }